Apparatus for magnetic spring testing



T. SPOCNER APPARATUs Foa M'AGNETc SPRING 'mas'mmsy Dec. 15, 1925 Filed-April 21, 1921 zsheezssheet 1 2 f, ma;

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WITNESSES: :1f-@f f ATTORNEY Dec. 15, 1925- 1.565.519 T. sPooNER APPARATUS Foa Mayans SPRING TESTING v Filed April 271, 1921 2 l:Smets-sheet 2 @JUN` A l WITNEssEs; y v A INVENTOR 325mm 'Thomas poonen AT'TORNEY,

Patented use 15, 1925. p

UNITED- STATES THOMAS SPOONEB, OFv EDGEWOOD PABX,

PATENT OFFICE.

PENNSYLVANIA, ASSIGNOR T WESTING- HOUSE ELECTRIC &VMANUFACTUBING COMPANY, .A CORPORATION OF PENNBYIi-- VANIA.

APPARATS FOB MAGNETIC SPRING TESTING.

Applicatioaled April 21, 1921. Serial Ilo.` 463,862.`

To all whom- 'may' concern.'

Be it known that I, THOMAS SrooNER, a citizen of the United States, and a resident of Edgewood Park, in the county of Alle gheny and State of.Pennsylvania, have invented a new and useful Improvement4 in Apparatus for Magnetic Spring Testing, of w ich the following is a specification.

This invention relates to testing of varil? tiesl of objects of iron or steel, such as hard' ened locomotive springs, quickly and accu-l rately without resorting to destructive tests.' The present invention is based upon the fact that any flaws in iron and similar ma 0 netic material placed in a magnetic e d cause'a distortion of the magnetic field, such ,distortion being measured by a suitable measuring instrument, such as a galvanometer. This invention also utilizes the hys- 5 teresis data for determining the composition of the material and heat treatment to which the Vmaterial was subjected.- For instance, the coercive force necessary to reduce the remanent magnetism to zero is a direct indi- I `cation of the hardness of the material.

A method of determining flaws in magneticmaterial which has been proposed, consists in magnetizing the sample to be tested b suitable means and then passing an exi lloring coil connected to a galvanometer along thesample. Flaws or defects -in the sample produce magnetic leakagl which changes the flux threadin throug the exploring coil, causing a de ection in the gall vanometer which is proportional to the amount of leakage at that point andis an accurate indication of the seriousness of the defect existing there.` l v My present inventionutilizes the princi'- ple of the aforesaid method and combines ;'witl 1 the same a method of and means for jobtaining the various hysteresis data, such as. maximum induction, reinanence and coercive force. l

4In practicing my invention, :I provide aD source of magnetizing current and pass such i current through a series of coils surrounding the spring or other object to` be tested. An 'exploring coil consisting of two differentially wound coils adapted "to be connected, either in series or separately, to suitable measuring instruments is so placed as to surround the spring. Suitable means are 'provided forrotating the spring within the magnetizing coils at a uniform rate, and the dee'ctions of the measuring instruments, as the coil passes over various sprin are noted. From the ata Athus obtaine an ilaws or defects in the material may readily be determined and the heatl treatment of the material may be accurately gauged thereby.

In the accomanying drawings forming a part hereof an whichillustrate one form of my invention, i'

arts ofthe Fig. 1 is an elevational view of the netizing member with a spring to be tested in lace;

1g. 2 1s a vertical sectional view 'of the ap aratus shown in Fig. l;

ig. 3 is a bottom plan view of the cap or connector member of the apparatus;

Fig. 4 is an inverted elevational view of the same;

Fig. 5 is an elevational view ofone of the U-shaped bars forming the magnetizing coil, and

Fig.' 6 is a dia amni'aticfview ,the

lap aratus and` its e ectrical 'connections- 'The testing,apparatuscomprises a basel.

of insulating material having an extension@ thereon, a plurality of, radial slots 3 being' formed in the extension 2. Uashaped bars 4 of conducting material, 'usually' .oo per,

are

(placed within slots `3 and exten upthe lower ends or.basesl thereof y being securely, fastenedA in said slots. :A member 6/of insulating-material placed near the uper'ends ofvbars 4 serves to hold them position. An opening 7 is provided in member 6.

A ca or connector member,8,`com osedA 'A of insu ating material, is provided with a series of depending spring contact members n i),disposed adjacent to its outer periphery" and a similar series of springcontact mem- 'bers v10 disposed adjaient'ltojitsenter, all' ofthe contact members being so placed as to allow the upper .ends of bars 4to lit vtherein. Conductormembers 11 are secured i vbetween pairs of contacts 9\and 10, as shown in'Fi s. 3 and 4, leaving two free ends 'which constitutev terminals 12 and 13 for connecf- 'tion to a suitable source of current. "When j the capf8 is placed uponl the testing device,

the contacts 9 vand 10 engage the ends of bars. 4 to form -a single coil, the free ends 'l2 and 13 of which are connected to a source oi' current.

Within the radially placed bars 4, at the fyns placed. The table-16 is grooved and carries a belt 19 adapted to be driven from any suitable source of power.

Coil 2O which consists of two coils of tine wire of about l() turns each, reversely wound, has connected thereto a 'handle 21.

Leads22, 23 and 24 from said coils are connected, in' a suitable manner,to either lfjof two measuring instruments.

s Leads 2,5,` connected to terminals 12 and r 13 of the magnetizingvcoiand havin a resistor 26 in' kthe circuit'are `'connected poles 29 ofa double-poledouble-throwre; versing switch 27, having'an o posite setj'o poles 28. The central -poleso :said

are connected to'fleads- 30 A, l suitable source 'of direct current.

ampere shunt being'placed in the circuit. Conductor leads 33 and 34 connected, resipectivel to one of the poles 28 and 'a iagonal y opposite pole 29 'are connected in circuit with a variable resistor 35. Switch 32, in shunt with leads 33 and 34, serves to short circuit the resistor 35. A

' millivoltmeter 36 and a 100' ampere shunt 37' are placed in the resistor circuit.

Leads23 and 24 are connected to the poles 38 and 39, respectively, of a doublethrow switch 40, a lead 41 being connected to the central pole thereof and to one of the central poles of a double-pole, double-throw switch 42. Lead 22 is connectedto the opn posite central pole of switch 42. Poles 43 thereof are connected, by suitable means, to

. galvanometer 44, and poles 45 are connected,

-byleads 46 and 47, t'o a ux meter 48, a 5? lvariable resistor 49 and a shunt resistancey f `-"'50 being placed in circuit.

f-lnorder to calibrate thelux meter 48,' `'an-inductance coil 51 is inserted in the line '47, the-mutual -inductance of said coil and i lo then opposing coil 52 being known. Coil 52 is' connected to dmible-pole, double-throw .f reversing" 'switch '53,' the central poles of which are connected to a' circuit containing a so'urce of current l54 and a variable resistance 55.'

' manera@ The operation 'of thedevicefor the de-` ring is as foltermination of flaws in a lows: Switch 27 is made-f o acontact with .i

lpoles 29; switch 42 with 'poles 43,and switch 40 with pole39, the switch 32 being vclosedmm lA current of'about 300 amperes is passed through leads 30, through switch 27, leads 25 andthemagnetizing coils of the test# ing device. A motor-60, which drives table 16 by means of beltj19, is energized throng switch 61 and source of current 62.

. Coil 20-is placedoverthe end of lspring 18 and, assa1d spring rotates, it causes thel deiecti'ons-being a measure ofthe liaws in .that part of the spring over which the coil 2O passes. The movement of the s ring is suk then reversed by reversing the irection of rotation of motor 60.

ln order to determine the hysteresis data,

switch 32 is closed and exploring coil 20 is moved down to a positionv approximately at the center of-s ring 18. Switch 42 is placed in contact wit poles 45 and switch 40 with y fpole 38. yCurrent is passed through the magnetiing coils as before, and the deections of the ux-meter 48 are read when switch 27 is reversed. In' this manner, the

I "maximum induction of the spring being i order to determine the remanence o voltmeter 31 is insertediin'line 30,.a 460 .tested is determined.

these conditions, the reading of millivoltmeter 36 gives the coercive oree.

My apparatus, above described, forl testing the guality of :hardened material is capable o use for the testing of materials ot er than springs and of forms different trom that shown and described. It will be apparent to those skilled in the art' that t e apparatus may be modifiied so that forms other than spirals or sprisl may be tested thereby, and that various modifications in the electrical connections may be made within the scope of my invention.

I claim as my invention:

1. Apparatus for testing helical s magnetic materials comprising aV cy indrical cage, a rotatable base for mounting a coil spring centrally therein, means for rotating rings of I rotating said base,'means for passing magl netic fiux through said spring, a coil adapted to be engaged with the spring to be tested and means connected to said coil for noting flux densities in said spring, said coil i being adapted. to ltraverse the convolutions of said spring during therotation of the latter.

3. Apparatus for testin magnetic materials comprising a base, -shaped conducting bars secured therein, a rotatable table for holding a body ,to be tested and a 4coil in proximity to said body, said coil being connected to a suitable measuring instrument.

5 4. Apparatus forv testing magnetic materials comprising a base, U-shaped conductf ing bars formin a closed circuit secured therein, a rotata le table :for holding a body to be tested and acoil in proximity to said body, said coil being connected to a 30 suitable measuring instrument.

5. Apparatus for testlng magnetic mate.-

rials comprising a base, U-shaped conductv.

ing bars secured therein, a rotatable table for holding'a body to be tested-between the A i legs of said U-shaped bars and a coil in proximity to said body, said coil being connected to a suitable measuring instrument.

6. Apparatus for testing magnetic materials comprising a base, radially placed U-shaped conductin a rotatable table or holdin a body to be tested and a coil in proximity to said body, said coil being connected to a suitable measuring instrument. .l

7. Apparatus for testing magnetic ma. terials comprising a base, U-shaped conductingl bars secured therein, a cap having a series of contactsA connecting said bars in series, a rotatable table for holding a body to vbe tested and a coil in proximity to said f body, said coil being connected to 'a suitable measuring instrument. l In testimony whereof, I have hereunt0- il. u i

subscribed my name this 11th dayof 1921. I

bars secured therein,

THOMAS 4 

